George W. Rusten started began working at the National Institutes of Health (NIH) in 1941 as a manual laborer while he was waiting for another job to start. As a manual laborer in 1941, Rusten performed a variety of tasks including cleaning out offices, cutting grass, digging ditches, and driving trucks. When the other job never opened, what was supposed to be a temporary position turned into a lifelong career at the NIH. In 1942, Rusten had a physical examination for a permanent position as a laborer, but the doctors detected a slight heart murmur and suggested he would need to do lighter work. For a short while he was the elevator operator in Building 5.

His first laboratory job came in 1943 in the glassware washing room of the Laboratory of Tropical Diseases in the former Microbiological Institute (now the National Institute of Allergy and Infectious Disease). Rusten had applied for the job of an under-scientific helper, but the job was later reclassified as a junior laboratory assistant.